Jarnsaxa

Giantess. Jarnsaxa or Iarnsaxa was the mother of Magni and Modi, by the Aesir Thor. Not much is known about Jarnsaxa, except that she was Sif's rival for Thor's love. All references to Jarnsaxa have to do with either Thor being her lover or Magni being her son. Her parents are unknown.

Her name means "iron sax". Her name appeared in Sturluson's list of giantesses, and in a couple of Eddaic kennings.

Every difficulty increases Iarnsaxa's wind in Olaf's father, so that praise is due.

Here, Iarnsaxa's wind means "courage".

He reddened with gore the chops of the dark-looking steed of Iarnsaxa....

In this kenning, the dark-looking steed of Iarnsaxa indicates that her steed was a wolf.